1) A Sense Of Humor – There is a time to be serious and get down to work, but being able to laugh is important too. You don’t necessarily need to be a prankster, but don’t take everything seriously.
2) Know the difference between venting and complaining – Sure. Everyone has their bad days. Things don’t always go smoothly. Let people know you’re having a bad day, then try to move on. Don’t become the human dark cloud who then evolves into a psychic vampire and drains the life and enthusiasm for being there. If things get that bad, dude; quit. If you are reading the classified during your lunch hour; it might be time to move on.
3) Flexible – Things don’t happen when they need to, nor does the equipment work the way it’s supposed to all the time. Figure out work arounds. Don’t go postal.
4) Be willing to help out where it’s needed – Don’t be the person who will literally only do the things specifically listed on your job description. Especially if you work in a small office, being willing to help others can go along way.
5) Beware of the psychological condition of TRANSFERENCE – If you just ended a customer call after getting your face ripped off because they didn’t get their way; don’t take it out on anyone. Empower yourself. Learn what you can and can’t do, then only worry about the stuff you can change. If a customer tries to rip you a new one, tell them you’re willing to help but not be abused. Be willing to help, but not willing to be a pariah for all the evils ever befallen from them in the past. Oh, and don’t go blaming the person or group who handled the issue before. Bad karma, otherwise.
Bonus trait: practice decent personal hygiene. Co-workers are willing to cut you some slack for the occasional broccoli in the teeth thing after lunch. Bad coffee breath is possible to cope with for brief periods. I am talking the shower/bath thing. Clean off. Use deoderant or other anti-stink technology.